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High concentrations of haptocorrin interfere with routine measurement of cobalamins in human serum and milk. A problem and its solution

2009; De Gruyter; Volume: 47; Issue: 2 Linguagem: Inglês

10.1515/cclm.2009.047

1437-4331

Dorte L. Lildballe, Tore Forsingdal Hardlei, Lindsay H. Allen, Ebba Nexø,

Enterobacteriaceae and Cronobacter Research

Abstract : Human milk and occasional serum samples contain high concentrations of unsaturated haptocorrin, which influence accurate measurement of cobalamins. : Cobalamins in serum samples spiked with increasing amounts of unsaturated haptocorrin were measured employing the Centaur, Cobas and Architect analysers. Cobinamide-coated EAH sepharose was employed for pretreatment of the samples. Human milk samples were collected from 24 healthy mothers. Haptocorrin was measured by ELISA. : The measured concentration of cobalamins either increased (Centaur analyser) or decreased (Architect, Cobas analysers) significantly for haptocorrin >10 nM, and was 220%, 52% or 45% of the expected values in a serum sample containing 50 nM haptocorrin. Following pretreatment with cobinamide-sepharose, the expected cobalamin concentration was obtained (Centaur). The milk samples contained 4.5–180 nM haptocorrin. In samples containing >10 nM haptocorrin (n=19), the median concentration of cobalamins decreased from 1.3 nM to 0.67 nM after pretreatment with cobinamide-sepharose. : Haptocorrin in concentrations above 10 nM influences measurement of cobalamins giving rise to falsely elevated or decreased results. Removal of unsaturated haptocorrin by pretreatment with cobinamide-sepharose solves the problem. Clin Chem Lab Med 2009;47:182–7.